1. Field of the Invention
The present invention relates to the field of an information process device, a delivery information input device, an information process method, and an information processing program. Specifically, it belongs to a technical field of an information process device that is mutually connected through a network such as internet and receives delivery information such as movie and music through the network, and a delivery information input device that inputs the delivery information to the network, an information process method for the information process device and the delivery information input device respectively, and an information processing program used in the information process device or the delivery information input device. The above-mentioned delivery information is simply referred to as “content” hereinafter.
2. Discussion of Related Art
Recently, a content delivery service such as VOD (video on demand) and internet television has been prevailed due to prevalence of a so-called broadband line.
What noticed is networks of a tree type and a grid type using a so-called P2P (Peer-to-Peer) network as a new mode alternative to a server client method that is a mainstream of delivery mode in a current content delivery service. In the P2P network, all terminal devices that participating in the network and receiving data delivery are connected through, for example, a network such as the internet. Here, concretely, these terminal devices are realized by a set top box, a personal computer, or the like that are connected to the above-mentioned network installed every home. In the P2P network, all or part of a processing unit and a memory unit installed in the respective terminal devices are provided to an entire network, and all the terminal devices share all loads that are generated by searching and sending and receiving content data subject to be delivered. Such the configuration enables the P2P network to solve disadvantages of the conventional server client method described above, that are concentration of access from respective terminal devices to a server as a delivery source and high administration cost of servers or the like. Here, as the conventional art related to a grid-type network using the P2P network, for example, Japanese Unexamined Patent Publication No. 2006-197400 described below is cited.
On the other hand, although having the above-mentioned characteristics, the P2P network has a disadvantage that the user of the other terminal device who is to be the other party to receive and send data through a network is not necessarily a reliable user of the terminal device in terms of information leak or the like. This disadvantage is caused by the fact that the terminal device configuring the network is the above-mentioned set top box, personal computer or the like. In the P2P network currently developed to solve this disadvantage, it is configured in such that so-called user authentication process is carried out when a new terminal device participates in the network itself, or an falsification check is carried out when content data are obtained through the network.
Here, the above-mentioned falsification check that is reviewed in the existing P2P network is briefly described.
Ordinarily, as a method of carrying out the falsification check process, there is a method using a so-called “hash value” that is corresponding to content data being a delivery subject. More particularly, in the existing P2P network, the above-mentioned hash value corresponding to a so-called metafile added to when respective contents are delivered is registered (described) in a catalog file used when contents communicable at that time are introduced to respective terminal devices. Further, the above-mentioned hash value corresponding to content data forming the content itself is registered (described) in the metafile. Upon completion of delivery of the content data to the terminal devices, comparison is made in the terminal device receiving the delivery between a hash value newly generated from the content data themselves thus delivered and the hash value previously described in the metafile. Based on this, in a case where thus compared both sides match or have a corresponding value, falsification is not made for the content data and it is verified that the delivery is normally completed. Here, a process of checking falsification of the above-mentioned catalog file itself is carried out by verifying a so-called digital sign included in respective catalog files, in terminal devices or the like.
Content delivery and a reproduction process in the terminal device under the condition that the falsification check process is carried out are briefly described.
First, a normal reproduction process for the content or a reproduction process at a normal reproduction speed is briefly described.
In a case where the delivered content is reproduced in the terminal device at a normal reproduction speed and an amount of content data corresponding to the content is large, a start of reproduction itself of the content may be greatly delayed when the above-mentioned falsification check is carried out after all the content data are prepared.
Then according to a conventional technique, all the content data corresponding to a single content are first divided into files having data amount previously set up and delivered. At respective timing where all the data of respective files thus divided are completely delivered, it is configured such that the above-mentioned falsification check process and subsequent reproduction process are carried out for data in the divided file, in the acquired terminal devices. Hereinafter, a single file thus divided is simply referred to as “slice file”.
Next, a double speed reproduction process for the content or a reproduction process at a reproduction speed of n-times (n>1) is briefly described.
Generally, a moving picture image of the above-mentioned content is formed of a series of plural static images that are referred to as “frame”. It often occurs that a one-second moving picture image is usually formed of 30 frames of static images. Reproduction of the moving picture image is realized by sequentially shifting displays of respective static images forming the moving picture image, at high speed. Hereinafter, a static image as a basis of the static image sequentially reproduced is referred to as “key frame”. In a case where, for example, the moving picture image is encoded on a basis of MPEG (Moving Picture Expert Group) standard, this key frame corresponds to a frame referred to as so-called “I (Intra-coded) picture”.
Further, in the above-mentioned double speed reproduction process, only key frame data corresponding to this key frame are used (in other words, reproduction of frames except for the key frame is skipped) and timing of sending this to a decoder of the terminal device is shifted to realize the double speed reproduction process. Here, the double speed reproduction process may be realized by sending singly key frame data to the decoder plural times, depending on a degree of double speed or the like.    Japanese Unexamined Patent Publication No. 2006-197400 (FIGS. 1 to 5 and so on)